Method for investing destructible patterns for inlay fillings



April 21, 1925.

J. CLINE METHOD FOR INVESTING'DESTRUCTIBLE PATTERNS FOR INLAY FILLINGS Filed Dec. 14, 1923 JEan 6/09 a ci ty of Portland, county of Multnomali, and v State of Oregon, have invented a certain new andhas become setit will Patented Apr. 21, 1925.

UNITED STATES JEAN cLmE, or PORTLAND, onneon.

'HETHQD' EOE INVESTING DESTBUCTIBLE PATTERNS FOR INLAY FILLINGS.

Application filed December 14, 1923. Serial no. 680,781.

To whom it concern: I

Be it known that I, JEAN CLINE, a citizen of'the United States, and a resident of the and useful Improvement in Methods for In vesting Destructible Patterns for Inlay Fillings, of which the following is a specification.

This invention relates to the making of castings and particularly to the making of dental castings which are used in gold inlay work, and the like.

As it is wellknown, the most common manner in which these castings are made is by making a'waximpression of the cavity in the patlents tooth and investing this wax impression or pattern with any composition sold in the .dental trade as investing material which usually consists in a large degree of plaster of Paris The composition is sold in a dry powdered state and requires the addition of water. The water must be mixed with the composition in definite proportions, as only a definite amount of the composition will take up only a definite amount of water, 'and thus if there is a rela- 'tlX'G excess of either material it will remain which is the exact size and shape of the cavity in the tooth and thus when the gold or other metal is pouredinto this cavity fit exactly into the cavity. 1

' I have noted that if the proportions .of

the composition are not exact and there is an excess of moisture the heat applied -to melt the wax impression will cause the water to be evaporated and leave holes or voids in the mold and thus as these holes communicatel withthe recess in the mold, resulting from the'wax impression, there will be'formed on the casting, small bubbles or projections which prevent the impression from fitting exactly into the toothand thus these minute before the casting can be used.

. portions of water, and thus it is very diflimoisture projections must be removed.

vesting the. wax impressiom or other de- I structible pattern, with an investment material 'WhlOh consists of a composition mixed with water so as to make a fluid, whichjsubsequently sets. due to chemical action, which will eliminate any excess or 'uncoinbined from the composltlon, as it 1s takmg its se A further and incidental object is to provide a method by which the investing material will form itself more closely about the impression or pattern so-as to make more nearly an exact replica thereof without sub-' jecting the minute and fragile parts to a force which would tend to deform them.

I attain these and other objects by providing a device consisting of an open top .container which has a hollow member or,

as it is known, an inlayring, seated therein. I provide a recess in the container which is provided with sealing means and I also make the portion of the container within said ho1low member convex and mount a destructible pattern thereon. I then pour this liquid investin material into the hollow member and su ject the device to centrifugal force whereby this composition investing material, which is mixed with water, 'sets and the chemical action takes place but the excess moisture is forced upwardly from the container due to its lighter specific gravity and the combined material sets in solid form at the bottom and surrounds the pattern. The container is preferably larger and higher than the ollow'membe'r containing the investing material and thus the excess moisture is forced over the top of the hollow member into the container in which it is trapped.

- The construction and operation of my device is described in the accompanying specification and is illustrated in the drawings in which: 1

Fig. 1 is an elevation of one of the sunplest means of utilizing my invention wlth luii a portion of the devices shown in sections illustrate details of construction;

Figs 2 is a section taken on the line 2-2 of Fig. 1; f

Fig. 3 is an enlarged fragmentary sectional view of my device and diagrammatically illustrates the the action of the device when subjected to centrifugal force;

Fig. 4 is an elevation of the container and a vessel for holding the investment material, and shows the parts separated but in'their approximate positions;

Fig. 5 is a. sectional view of the hollow member containing the investment or cementitious matrix material after it has become set and the destructible pattern removed.

The device shown in the accompanying drawings comprises abucket a which'has, a removable bottom I) and the top of which is substantially closed by a funnel shaped vessel 0. Both the bottom I) and the funnel shaped ve$el 0 are removably secured by a mechanism which holds them rigidly in place when being used but permits them to be readily detached. -One type of mechanism of this character is the bayonet joint, which is shown in Fig. 4, which consists of an L-shaped slot d in. which the pin 6 fits, this joint being used to hold the funnel shaped vessel in the cylindrical container and a similar slot (2 is provided on the removable bottom which co-operates with the pin 6 on the lower portion of the cylindric'al container at and is used for holding the removable bottom in place. The bottom is provided with a trough f in which the hollow inlay ring 9 is mounted. I preferably fill this trough f with some viscous material such as beeswax, as shown at h,

in which the inlay ring may be seated and.

the material serving to make a water-tight joint around the bottom of the inlay ring. I make the central portion of the removable bottom 11 raised as at i, so that it is substantially convex, and I. provide a small aperture in the apex as j in which I mount the hollow pattern-mounting pin which supports the destructible pattern or wax impression Z which is to be nvested.

I usually provide a piece of wax or similar material as m in which the hollow pattern-mounting-pin 70 is secured. Said pin constituting an outlet from the vessel 0 has an aperture a in its lower surface so that it substantially like a funnel, and this aperture is preferably arranged directly over the center of the hollow member or inlay ring and thus when the investing material 0 is placed in the vessel 0 it will be directed so i as to fill the inlay ring 9. I preferably provide a protecting lip 32 over the vessel 0 and provide a filling aperture q in this lip and I provide a bail r for the container which has an eye 8,. which is permitted to swivel therein. On this eye I provide a handle t which has a hook on the lower end t and is provided with agripping portion u, which is preferably at right angles thereto. The handle u is either rotatably mount- The reason I provide this protecting lip p is that when the device is first rotated and the action of the centrifugal force is not very strong, the investing material tends to overflow from the vessel and thus be thrown about ,the room. This is especially true if the centrifugal force is occasioned by arranging the vessel to be whirled by a machine. This protecting lip p is made'with a relatively small hole and thus the investing material is held in the vessel even in thepreliminary stage of rotation.

The operation of my device is as follows:

Ifmy invention is used for making castings' for inlay filling, the wax impression is mounted on the end of the hollow pin 70,

is inserted in the hole 7', and fixed in place inside of the inlay ring g. This inlay ri is seated firmly into the sealing material i and the bottom is then placed on the container and fastened thereto by the bayonet joints composed of the pins e and the slot at. The vessel 0 is then placed in position so that the aperture n will be directly above the inlay ring 9 and then the vessel is filled with the matrix material. The bucket is then swung around by the handle t and the action of the centrifugal force so set up tends to feed this material from the vessel 0 out through the aperture n and into the inlay ring 9 so that it surrounds and is packed around the-wax impression or destructible pat-tern f. The ring is thus gradually filled with this composition investing material and is' prevented from seeping out of the bottom of the inlay ring by the sealing material la. The quantity of. material placed in the vessel 0 is preferably proportioned so that itis slightly in excess of the amount held by the inlay ring g. The centrifugal force tends to separate the moisture from the solid material and causes the latter to completely invest the pattern. Thus, as the inlay ring 9 is filled, the water is forced upwardl until it overflows the top, as g, of

v the in ay ring. This moisture is trapped in of investing with which I am familiar.

I claim: I 2. The method of investing a destructible '1 1. The method of investing a destructible pattern for an inlay filling consisting in pattern for an inlay filling consisting in mounting the pattern in a container, then mounting the pattern in acontainer,then fillgradually filling the latter with an invest- 5 ing the latter with an investing composition ingcomposition until the pattern is comuntil the pattern is completely covered, and pletely covered, and subjecting the composi- 15 subjecting the composition to centrifugal tion to centrifugal force until the excess force until the excess moisture is separated moisture is separated therefrom.

therefrom. JEAN CLINE}: 

